In this study, the authors cloned a glycosyltransferase gene PpUGT2 from Paris polyphylla var. yunnanensis with the ORF length of 1 773 bp and encoding 590 amino acids. The phylogenetic tree revealed that PpUGT2 belonged to the UGT80A subfamily and was named as UGT80A49 by the UDP-glycosyltransferase(UGT) Nomenclature Committee. The expression vector pET28a-PpUGT2 was constructed, and enzyme catalytic reaction in vitro was conducted via inducing protein expression and extraction. With UDP-glucose as sugar donor and diosgenin and pennogenin as substrates, the protein was found with the ability to catalyze the C-3 hydroxyl β-glycosylation of diosgenin and pennogenin. To further explore its catalytic characteristic, 15 substrates including steroids and triterpenes were selected and PpUGT2 showed its activity towards the C-17 position of sterol testosterone with UDP-glucose as sugar donor. Homology modelling and molecule docking of PpUGT2 with substrates predicted the key residues interacting with ligands. The re-levant residues of PpUGT2-ligand binding model were scanned to calculate the corresponding mutants, and the optimized mutants were obtained according to the changes in binding affinity of the ligand with protein and the surrounding residues within 5.0 Å of ligands, which had reference value for design of the mutants. This study laid a foundation for further exploring the biosynthetic pathway of polyphyllin as well as the structure of sterol glycosyltransferases.
Ligands ; Glycosyltransferases/genetics* ; Sterols ; Phylogeny ; Ascomycota ; Liliaceae/chemistry* ; Melanthiaceae ; Diosgenin ; Sugars ; Glucose ; Uridine Diphosphate

Biorefinery of chemicals from straw is an effective approach to alleviate the environmental pollution caused by straw burning. In this paper, we prepared gellan gum immobilized Lactobacillus bulgaricus T15 gel beads (LA-GAGR-T15 gel beads), characterized their properties, and established a continuous cell recycle fermentation process for D-lactate (D-LA) production using the LA-GAGR-T15 gel beads. The fracture stress of LA-GAGR-T15 gel beads was (91.68±0.11) kPa, which was 125.12% higher than that of the calcium alginate immobilized T15 gel beads (calcium alginate-T15 gel beads). This indicated that the strength of LA-GAGR-T15 gel beads was stronger, and the strain was less likely to leak out. The average D-LA production was (72.90±2.79) g/L after fermentation for ten recycles (720 h) using LA-GAGR-T15 gel beads as the starting strain and glucose as the substrate, which was 33.85% higher than that of calcium alginate-T15 gel beads and 37.70% higher than that of free T15. Subsequently, glucose was replaced by enzymatically hydrolyzed corn straw and fermented for ten recycles (240 h) using LA-GAGR-T15 gel beads. The yield of D-LA reached (1.74±0.79) g/(L·h), which was much higher than that of using free bacteria. The wear rate of gel beads was less than 5% after ten recycles, which indicated that LA-GAGR is a good carrier for cell immobilization and can be widely used in industrial fermentation. This study provides basic data for the industrial production of D-LA using cell-recycled fermentation, and provides a new way for the biorefinery of D-LA from corn straw.
Fermentation ; Lactobacillus delbrueckii ; Zea mays ; Lactic Acid ; Alginates/chemistry* ; Glucose

β-glucosidase has important applications in food, pharmaceutics, biomass conversion and other fields, exploring β-glucosidase with strong adaptability and excellent properties thus has received extensive interest. In this study, a novel glucosidase from the GH1 family derived from Cuniculiplasma divulgatum was cloned, expressed, and characterized, aiming to find a better β-glucosidase. The amino acid sequences of GH1 family glucosidase derived from C. divulgatum were obtained from the NCBI database, and a recombinant plasmid pET-30a(+)-CdBglA was constructed. The recombinant protein was induced to express in Escherichia coli BL21(DE3). The enzymatic properties of the purified CdBglA were studied. The molecular weight of the recombinant CdBglA was 56.0 kDa. The optimum pH and temperature were 5.5 and 55 ℃, respectively. The enzyme showed good pH stability, 92.33% of the initial activity could be retained when treated under pH 5.5-11.0 for 1 h. When pNPG was used as a substrate, the kinetic parameters K_m, V_max and K_cat/K_m were 0.81 mmol, 291.99 μmol/(mg·min), and 387.50 s^-1 mmol^-1, respectively. 90.33% of the initial enzyme activity could be retained when CdBglA was placed with various heavy metal ions at a final concentration of 5 mmol/L. The enzyme activity was increased by 28.67% under 15% ethanol solution, remained unchanged under 20% ethanol, and 43.68% of the enzyme activity could still be retained under 30% ethanol. The enzyme has an obvious activation effect at 0-1.5 mol/L NaCl and can tolerate 0.8 mol/L glucose. In conclusion, CdBglA is an acidic and mesophilic enzyme with broad pH stability and strong tolerance to most metal ions, organic solvents, NaCl and glucose. These characteristics may facilitate future theoretical research and industrial production.
beta-Glucosidase ; Sodium Chloride ; Temperature ; Glucose ; Ethanol/chemistry* ; Ions ; Hydrogen-Ion Concentration ; Enzyme Stability ; Substrate Specificity

This study aimed to examine the effect and underlying mechanism of Puerariae Lobatae Radix on insulin resistance in db/db mice with type 2 diabetes mellitus(T2DM) based on the analysis of intestinal flora. Fifty db/db mice were randomly divided into a model group(M group), a metformin group(YX group), a high-dose Puerariae Lobatae Radix group(YGG group), a medium-dose Puerariae Lobatae Radix group(YGZ group), and a low-dose Puerariae Lobatae Radix group(YGD group). Another 10 db/m mice were assigned to the normal group(K group). After continuous administration for eight weeks, body weight and blood sugar of mice were measured. Enzyme linked immunosorbent assay(ELISA) was used to detect glycosylated serum protein(GSP) and fasting serum insulin(FINS), and insulin resistance index(HOMA-IR) was calculated. The histopathological changes in the pancreas were observed by HE staining. Tumor necrosis factor(TNF)-α expression in the pancreas was detected using immunohistochemistry. The structural changes in fecal intestinal flora in the K, M, and YGZ groups were detected by 16S rRNA. Western blot was used to detect the expression of farnesoid X receptor(FXR) and takeda G protein-coupled receptor 5(TGR5) in the ileum, cholesterol 7α-hydroxylase(CYP7A1) and sterol 27α-hydroxylase(CYP27A1) in the liver, and G protein-coupled receptors 41(GPR41) and 43(GPR43) in the colon. Compared with the K group, the M group showed increased body weight, blood sugar, serum GSP, fasting blood glucose(FBG), and FINS, increased HOMA-IR, inflammatory infiltration of islet cells, necrosis and degeneration of massive acinar cells, unclear boundary between islet cells and acinar cells, disturbed intestinal flora, and down-regulated FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43. Compared with the M group, the YX, YGG, YGZ, and YGD groups showed decreased body weight, blood sugar, serum GSP, FBG, and FINS, islet cells with intact and clumpy morphology and clear boundary, necrosis of a few acinar cells, and more visible islet cells. The intestinal flora in the YGZ group changed from phylum to genus levels, and the relative abundance of intestinal flora affecting the metabolites of intestinal flora increased. The protein expression of FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43 increased. The results show that Puerariae Lobatae Radix can improve the inflammatory damage of pancreatic islet cells and reduce insulin resistance in db/db mice with T2DM. The mechanism of action may be related to the increase in the abundance of Actinobacteria, Bifidobacterium, and Bacteroides in the intestinal tract and the protein expression related to metabolites of intestinal flora.
Mice ; Animals ; Insulin Resistance ; Blood Glucose/metabolism* ; Diabetes Mellitus, Type 2/genetics* ; Pueraria/chemistry* ; Gastrointestinal Microbiome ; RNA, Ribosomal, 16S ; Body Weight ; Necrosis

The tea beverages will be endowed with distinct aroma and taste, as well as various biologically active compounds including probiotic factors, when fermented with lactic acid bacteria (LAB). However, at present, few studies on the dynamics of flavors in tea soup at different fermentation stages were conducted. In this study, the composition of monosaccharides, aromatic components, free amino acids, and organic acids were measured, when the black tea beverages were fermented with Lactobacillus coryniformis FZU63 which was isolated from Chinese traditional kimchi. The results indicated that monosaccharides including glucose, fructose, mannose and xylose in black tea beverages are the main carbon sources for fermentation. In addition, the abundance of aromatic compounds in black tea soup are increased significantly at different fermentation stages, which endow the fermented black tea soup with fruit aroma on the basis of flowery and nutty aroma. Moreover, some bitter amino acids are reduced, whereas the content of sweet and tasty amino acids is elevated. Furthermore, the levels of lactic acid, malic acid, citric acid and other organic acids are accumulated during the fermentation. Additionally, sensory evaluation displays that black tea beverage is acquired with comprehensive high-quality after being fermented for 48 h. This study provides a theoretical basis to steer and control the flavor formation and quality of the fermented tea beverages during LAB fermentation.
Tea/chemistry* ; Beverages/microbiology* ; Camellia sinensis ; Fermentation ; Acids ; Amino Acids ; Glucose

In this study, insulin (insulin, INS)/Ca₃PO₄ complex and glucose oxidase (glucose oxidase, GOx)/Cu₃(PO₄)₂ complex were prepared by coprecipitation method. The mineralized insulin (mineralized insulin, m-INS) showed irregular crystalline clusters, and the mineralized glucose oxidase (m-GOx) showed flower spherical morphology, with a diameter of about 1-2 μm. In vitro simulated release experiment showed that m-INS released INS as the pH value of the medium decreased. When the pH value was 4.5, the release amount reached 96.68%. The enzyme activity detection experiment showed that the enzyme activity stability of m-GOx was higher than that of free GOx. It still maintained high activity after 10 days at room temperature, while the activity of GOx was less than 60%. The glucose solution was prepared to simulate the state of normal blood glucose (5.6 mmol/L) and hyperglycemia (22.2 mmol/L). When m-INS and m-GOx were added to the glucose solution, the release amount of INS showed a significant glucose concentration dependence. The higher the glucose concentration, the greater the release amount and release rate of INS. Finally, m-INS, m-GOx and hyaluronic acid (HA) solution were mixed to prepare HA microneedle arrays loaded with m-INS and m-GOx. Type 1 diabetes mice were constructed to evaluate the effect of drug-loaded HA microarray on blood glucose control in diabetic rats. The results show that the HA microneedles loaded with m-INS/m-GOx could deliver drugs effectively. The average blood glucose concentration in diabetic rats dropped to about 7 mmol/L within 1 h, normal blood glucose concentration could be maintained for 10 h, and the overall blood glucose concentration was lower than the level before administration for 36 hours. Compared with HA microneedles loaded with INS only, m-ins microneedles showed better glucose tolerance, longer-lasting glucose control effect and less risk of hypoglycemia. Compared with other sustained-release systems, the preparation process of the core components in this study is simple, efficient, safe and effective, and has great commercial potential.
Animals ; Blood Glucose ; Delayed-Action Preparations/therapeutic use* ; Diabetes Mellitus, Experimental/drug therapy* ; Drug Delivery Systems/methods* ; Glucose Oxidase/chemistry* ; Hyaluronic Acid ; I Blood-Group System ; Insulin/therapeutic use* ; Mice ; P Blood-Group System ; Rats

The present study investigated the chemical constituents from Uncaria sessilifructus and their neuroprotective activities. The compounds were separated and purified from the 90% ethanol extract of U. sessilifructus by various chromatographic methods, including silica gel, Sephadex LH-20, and semi-preparative HPLC. Seven compounds were obtained, and their structures were identified as uncanidine J(1), uncanidine K(2), 17-O-ethylhirsutine(3), tetrahydroalstonine(4), akuammigine(5), hirsutine(6), and hirsuteine(7) by physicochemical properties and various spectral techniques, including UV, IR, MS, and NMR. Compounds 1 and 2 are two new compounds. Compound 3 is a new natural product, and compound 4 was isolated from U. sessilifructus for the first time. In addition, the isolated compounds were evaluated for their neuroprotective effects on oxygen and glucose deprivation/reoxygenation(OGD/R) injury in primary cortical neurons in rats. The results showed that compounds 1-7 had different degrees of protective effects on OGD/R injury. The EC_(50) values of compounds 2-4 were(0.17±0.03),(1.70±0.38), and(1.79±0.23) μmol·L~(-1), respectively.
Animals ; Biological Products ; Drugs, Chinese Herbal/pharmacology* ; Ethanol ; Glucose ; Indole Alkaloids ; Neuroprotective Agents/pharmacology* ; Oxygen ; Rats ; Secologanin Tryptamine Alkaloids ; Silica Gel ; Uncaria/chemistry*

Repeated silica gel column chromatography, reversed-phase C_(18) column chromatography, Sephadex LH-20 column chromatography, high performance liquid chromatography and semi-preparative medium pressure liquid chromatography were performed to separate and purify the chemical constituents of Hypericum lagarocladum. Spectroscopic methods such as mass spectrometry(MS) and nuclear magnetic resonance(NMR) combined with physicochemical properties were adopted in identifying the structure of the isolated compounds. Ten compounds were isolated from the ethyl acetate fraction of H. lagarocladum and identified as lagarxanthone A(1), 1,7-dihydroxyxanthone(2), 3,4,5-trihydroxyxanthone(3), 2,7-dihydroxy-1-methoxyxanthone(4), 1,3-dihydroxy-7-methoxyxanthone(5), 1,5-dihydroxy-8-methoxyxanthone(6), 3,4-dihydroxy-2-methoxyxanthone(7), 3,4-dihydroxy-5-methoxyxanthone(8), 2,3-dimethoxyxanthone(9), and 2,3,4-trimethoxyxanthone(10). Among them, compound 1 was a new compound, and compounds 2-10 were isolated from this plant for the first time. These ten compounds were tested for glucose uptake in L6 cells, and the results showed that all the compounds had no significant effect on glucose uptake.
Hypericum/chemistry* ; Xanthones ; Chromatography, High Pressure Liquid ; Magnetic Resonance Spectroscopy ; Glucose

Animals ; Blood Glucose ; Diet, High-Fat/adverse effects* ; Fatty Liver/metabolism* ; Lipid Metabolism ; Lipids/blood* ; Liver/metabolism* ; Mice ; Mice, Knockout, ApoE ; Plant Extracts/pharmacology* ; Raphanus/chemistry* ; Seeds/chemistry*

OBJECTIVE: To investigate the regulatory effect of iridoid glycoside of radix scrophulariae (IGRS) on endoplasmic reticulum stress induced by oxygen-glucose deprivation and reperfusion METHODS: Rat pheochromocytoma PC12 cells were pretreated with IGRS (50, 100, 200 μg/mL) for 24h, and the RESULTS: The damage caused by OGD/R to PC12 cells was significantly reduced by IGRS, with significant effect on increasing survival rate and reducing LDH release (all CONCLUSIONS IGRS has neuroprotective effect, which may alleviate cerebral ischemia-reperfusion injury by regulating SERCA2, maintaining calcium balance, and inhibiting endoplasmic reticulum stress-mediated apoptosis.
Animals ; Cell Survival/drug effects* ; Down-Regulation/drug effects* ; Endoplasmic Reticulum Stress/drug effects* ; Glucose ; In Vitro Techniques ; Iridoid Glycosides/pharmacology* ; Oxygen ; PC12 Cells ; Rats ; Reperfusion ; Reperfusion Injury/prevention & control* ; Snails/chemistry*